Show by sputum cytologic analysis the gradual development of malignant lesions in human lung from mild, moderate, and marked squamous cell metaplasia to carcinoma in situ and finally invasive carcinoma, determining the length of time in each stage. Continue the study of biology of human lung cancer by comparison of sputum cytology with histopathology at autopsy. Continue cooperative sputum cytology. Continue determinations of the level of CEA in uranium miners using the protocol specified by the Project Officer.